1. Field of the Invention
The present invention relates to a slave device being connected to a master device through a network and having a communication port for connecting a device.
2. Description of Related Art
In the past, there is a known master-slave control system, which includes a master device and a slave device connected to the master device through a network.
For example, a programmable controller is recorded in the following patent document 1, in which an input/output unit connected to a basic unit is replaced with an input/output unit of the same variety under the condition of no comparison and judgment.